Top White House economic adviser Larry Kudlow suffered a heart attack and is being treated at a Washington-area hospital, President Donald Trump said in a tweet.

"Our Great Larry Kudlow, who has been working so hard on trade and the economy, has just suffered a heart attack.

He is now in Walter Reed Medical Center," Trump said on Twitter minutes before he was scheduled to meet with North Korean leader Kim Jong Un in Singapore.

A longtime television commentator, Kudlow, 70, was hired by Trump in March to replace Gary Cohn as director of the National Economic Council.

(Image: AFP)

Kudlow joined the president at the Group of Seven summit in Quebec on Friday and Saturday.

He did several media interviews on Sunday to vigorously defend Trump after the president's trade spat with summit host Canadian Prime Minister Justin Trudeau.

(Image: AFP)

Kudlow, a Republican who served as an economic adviser to former President Ronald Reagan in the 1980s and also worked on Wall Street, is an ardent advocate of "supply side" economic policies that focus on cutting taxes and reducing regulations.

Kudlow has acknowledged ups and downs in his life, having been addicted to drugs and alcohol before getting sober more than 20 years ago.